Real-Time Downhole Zonal Gas Composition Tool for Production Logging

Abstract

There is currently no production logging tool that can analyze insitu gas composition in wells that intersect more than one pay zone. In high-value gas wells zonal isolation is useful for enhanced oil recovery (EOR) applications such as injection monitoring, pressure maintenance, and identification of layers that contain low-calorific-value gas. To unlock these key applications related to gas reservoir management, a new production logging tool (PLT) has been developed that introduces downhole gas composition analysis to the PLT string. The prototype has been tested in a gas storage well and a producing well. For gas field applications with pressures more than 3,000 psi, the estimated mole fraction errors in continuous logging mode are ~2% for methane and ~1% for ethane, propane, nitrogen, and carbon dioxide.